Last year, the challenge was a four-day race across the Sahara Desert to raise money for charity.

So when a group of Ventura County sheriff's deputies wanted to do another running fundraiser this year, they knew they had to up the ante. Instead of tackling one of nature's great creations, they are taking on one of man's: the Great Wall of China.

Six deputies will leave Monday to run a 26.2-mile race across the wall, which includes 8,000 steps, in an effort to raise money for three children's charities. So far, they have raised about $15,000 and gotten in really good shape.

"It's one of the hardest races in the world," said Capt. Randy Pentis, who is running with Sgt. Frank Underlin, Sgt. Paul Higgason, Capt. Tim Hagel, Sgt. Dave Kenney and Deputy Peter Frank.

Race organizers advise runners that the wall has many different-sized stairs, so the group is training by going up and down the stairs of the Camarillo High School football stadium and running through the hills of La Jolla Canyon.

Tripping could be the race's biggest hazard. Pentis said the wall is so steep that in places there's a rope to hold onto in case you fall.

"If you fall, you fall straight to hell," Pentis said.

Paramedics are nearby to treat runners for rope burn if they grab the rope too hard to stop a fall, he said.

Cops Running For Charity, as the group is called, has been running races for about three years.

They pay for all expenses themselves, use their own vacation time and 100 percent of the donations go to charity. This year's charities are Make-a-Wish Foundation, Childrens Hospital Los Angeles and the Juvenile Diabetes Research Foundation.

Pentis said as much as the fundraisers are fun, they also help elevate the profile of the Sheriff's Department.

"We hope that we bring some respect to the Ventura County Sheriff's Department where people can see that we are not only cops," said Pentis, who has one son who has stayed at Childrens Hospital and another who is diabetic.

After this race, the team is eyeing another one next year: four marathons in four days across Namibia in southern Africa.

Tax-deductible donations can be sent c/o CRFC to the East County Sheriff's Station, 2101 E. Olsen Road, Thousand Oaks, CA 91360.